Method and apparatus for rasterization
View Patent ↗The application provides a method for rasterization. According to the method, a primitive may be divided, at a position where a color abruptly changes in the primitive, into a plurality of sub-primitives with continuously and gradually changing colors. Each of the sub-primitives is then rasterized. The present application further provides an apparatus for rasterizing an image. The apparatus may comprise a dividing module configured to divide a primitive at a position where a color abruptly changes into a plurality of sub-primitives with continuously gradually changing colors. Furthermore, the apparatus may comprise a rasterizing module configure to rasterize each of the sub-primitives. The application may improve the speed of the rasterization and the quality of the processed image.
1. A method for rasterizing a primitive of an image, comprising:
dividing the primitive at a position where a color discontinuously changes into a plurality of sub-primitives with continuously changing colors; and
rasterizing each of the sub-primitives,
wherein the step of rasterizing further comprises:
setting respective resolution reduction coefficient nBlockSize for each sub-primitive in accordance with a ratio of the color change to the spatial size of each sub-primitive;
reducing the resolution of each sub-primitive based on the respective resolution reduction coefficient;
rasterizing each sub-primitive with the reduced resolution; and
increasing the resolution of the rasterized sub-primitive to the original resolution, and
wherein the step of setting respective resolution reduction coefficient further comprises:
taking the maximum value max (d(s i )/d(l)) as a quantized value for the color change, wherein (d(s i )/d(l)) is a derivative with resect to a spatial length l for the spatial color function of the sub-primitive in each color field, where s i is a spatial color function in i th color field; and
setting the resolution reduction coefficient of the sub-primitive nBlockSize based on the quantized value max (d(s i )/d(l)) as follows:
n BlockSize= L d /( S max /max( d ( s i )/ d ( l ))),
where L d is a spatial length in the radial direction of the sub-primitive, and S max is the maximum color difference in the range of the sub-primitive.
2. The method according to claim 1 , wherein the step of dividing further comprises:
scanning a shape and structure description of the primitive to obtain a plurality of spatial positions (C);
determining a plurality of position parameters (t) for the scanned spatial positions;
dividing the primitive at a position corresponding to discontinuous position parameters of the determined position parameters.
3. The method according to claim 1 , wherein the step of dividing further comprises:
scanning a spatial color function of the primitive to determine whether it is a piecewise continuous function, and
dividing the primitive at a position between each adjacent two pieces of the piecewise continuous function.
4. The method according to claim 1 , further comprising:
generating a clip path for each sub-primitive with continuously changing colors; and
defining a range of each sub-primitive in accordance with the respective clip path such that the resolution of the rasterized sub-primitives is increased within the defined range.
5. An apparatus for rasterizing a primitive of an image, comprising:
a dividing module configured to divide the primitive at a position where a color discontinuously changes into a plurality of sub-primitives with continuously changing colors; and
a rasterizing module configured to rasterize each of the sub-primitives,
wherein the rasterizing module comprises:
a coefficient setting module configured to set respective resolution reduction coefficient nBlockSize for each sub-primitive based on the ratio of the color change to a spatial size of each sub-primitive; and
a reducing resolution module configured to reduce the resolution of each sub-primitive based on the respective resolution reduction coefficient;
a performing module configured to rasterize the sub-primitive with the reduced resolution; and
a recovering module configured to increase the resolution of the rasterized sub-primitive to the original resolution, and
wherein the coefficient setting module comprises:
a derivation module configured to take a derivative (d(s i )/d(l)) with resect to a spatial length for the spatial color function of the sub-primitive in each color field, where s i is a spatial color function in i th color field and l is a spatial length;
a quantizing module configured to take the maximum value max (d(s i )/d(l)) as a quantized value for the color change; and
a calculating module configured to set the resolution reduction coefficient of the sub-primitive nBlockSize based on the quantized value max (d(s i )/d(l)) as follows:
n BlockSize= L d /( S max /max( d ( s i )/ d ( l ))),
where L d is a spatial length in the radial direction of the sub-primitive, and
S max is the maximum color difference in the range of the sub-primitive.
6. The apparatus according to claim 5 , wherein the dividing module further comprises:
a first scanning module configured to scan a shape and structure description of the primitive to obtain a plurality of spatial positions (C);
a first dividing module configured to determine a plurality of position parameters (t) for the scanned spatial positions, and divide the primitive at a position corresponding to discontinuous position parameters of the determined position parameters.
7. The apparatus according to claim 6 , wherein the dividing module further comprises:
a second scanning module configured to scan a spatial color function of the primitive to determine if it is a piecewise continuous function; and
a second dividing module configured to divide the primitive at a position between each adjacent two pieces of the piecewise continuous function.